diff --git a/ICD.Common.Utils/Collections/INotifyCollectionChanged.cs b/ICD.Common.Utils/Collections/INotifyCollectionChanged.cs
new file mode 100644
index 0000000..0d81aac
--- /dev/null
+++ b/ICD.Common.Utils/Collections/INotifyCollectionChanged.cs
@@ -0,0 +1,14 @@
+using System;
+
+namespace ICD.Common.Utils.Collections
+{
+	// Poor-mans System.Collections.Specialized
+	// Delete when we finally drop Crestron 3-series.
+	public interface INotifyCollectionChanged
+	{
+		/// <summary>
+		/// Raised when the contents of the collection change, or the order changes.
+		/// </summary>
+		event EventHandler OnCollectionChanged;
+	}
+}
diff --git a/ICD.Common.Utils/ICD.Common.Utils_SimplSharp.csproj b/ICD.Common.Utils/ICD.Common.Utils_SimplSharp.csproj
index 22b20ea..462ff4e 100644
--- a/ICD.Common.Utils/ICD.Common.Utils_SimplSharp.csproj
+++ b/ICD.Common.Utils/ICD.Common.Utils_SimplSharp.csproj
@@ -80,6 +80,7 @@
     <Compile Include="Attributes\RangeAttribute.cs" />
     <Compile Include="Collections\BiDictionary.cs" />
     <Compile Include="Collections\IcdOrderedDictionary.cs" />
+    <Compile Include="Collections\INotifyCollectionChanged.cs" />
     <Compile Include="Collections\PriorityQueue.cs" />
     <Compile Include="Collections\RateLimitedEventQueue.cs" />
     <Compile Include="Collections\WeakKeyDictionary.cs" />